Refrigerant evaporator



July 28,1942. R. c. WARNEKE REFRIGERANT EVAPORATOR I Filed Sept. 16, 1,941

Inventor Roman C. Warneke, b W 6.

His Attorney.

Patented July 28, 1942 'UNITED STATES PATEN T OFFICE.

REFRIGEBANT EVAPORATOR.

Roman C. V'Vameke, Fort Wayne, Ind" asa'ignor to General Electric Company, incorporation of New York h Application September 16, 1m, sci-m1inducer-1 ll Claims.

My invention relates to refrigerant evaporators or cooling elements for refrigerating machines. 7 One form of refrigerant evaporator comprises a continuous refrigerant vaporizing conduit or passageway through which liquid refrigerant is circulated and in which the liquid is vaporized by the absorption of heat. When the supply of liquid refrigerant to the'evaporator is controlled byan expansion device of the fixed restrictor sor. A liquid trap may be provided at the discharge end of a continuous conduit evaporator to collect liquid refrigerant discharged from. the evaporator and to prevent its entry into the suction line. Since the liquid trap is not an eflicient portion of the evaporator surface, it is desirable to return the liquid refrigerant to the evaporator so that the evaporation of the liquid may take place where it is most effective.

Some lubricating oil is unavoidably discharged from the compressor with the compressed refrigerant and becomes mixed with the liquid refrigerant in the evaporator. It is necessary to return this oil to the compressor in order to avoid its being trapped in the evaporator. This may be accomplished by permitting small amounts of the mixed liquid refrigerant and oil to enter, the

suction line. However, this must be accomplished without permitting slugs of liquid to enter the suction line. The small amounts of liquid which enter the suction line are heated to vaporize the liquid refrigerant and allow the lubricating oil to return to the compressor free of liquid refrigerant.

Evaporators of the continuous conduit type are frequently employed in wet type coolers for bottled beverages and the like, and are arranged at,

the bottom of a tank which may be filled with water in which the bottles to be cooled are placed. It is desirable to provide free circulation of water over the evaporator and, if a liquid trap is employed at the end of the evaporator, to arrange it so that it will occupy a minimum of space in the cooling tank.

continuous or series conduit evaporator of improved construction.

Another object of my invention is to provide a cooling unit including a continuousor series conduit evaporator having an improved arrangement for trapping liquid refrigerant at the outlet end of the "evaporator and for returning the liquid refrigerant to the evaporator. v

It is another object of my invention to provide an evaporator having an improved arrangement for facilitating the removal of lubricating oil therefrom.

Further objects and advantages of my inventlon will become apparentas the following description proceeds, and the features ofnovelty which characterize my invention. will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawing, in which Fig. l is a perspective view of a wet type beverage cooler provided with an evaporator em odying my invention; Fig. 2 is a diagrammatic view of the evaporator of Fig. l

frigerating machine; and Fig. 3 is an enlarged sectional perspective view of a portion of the evaporator shown in Fig. l.

The, evaporator shown in the drawing com prises a continuous conduit formed of extruded metal and comprises a refrigerant tube having a longitudinal flange, the tube being arranged in sinuous or zigzag form in a horizontal plane with the flange extending laterally from the plane. The evaporator is arranged in the bottom of the cooling tank of a wet type bottled beverage cooler. Inoraer to provide a rigid coil structure a portion of the evaporator conduit is bent back upon itself and welded or otherwise suitably bonded to one or more of the zigzag turns to provide one or more rigid loops. Liquid refrigerant is supplied to the evaporator from a compression type refrigerating machine through a capillary tube expansion device, and a liquid trap is provided at the outlet end of the evaporator so that sums of liquid refrigerant are prevented from entering the suction line. the liquid trap or header is construcvedas an upright elongated cylindrical chamber which'may be located in one corner of .tne cooling tank where it is out of the way. The refrigerant conduit of the evaporator enters the bottom of the trap and extends upwardly where it opens into the-top of the trap. in order to return liquid refrigerant from the trap to the It is an object of my invention to provide a evaporator co duit. 381ml! 0m aperture 18 connected in the refrigerant circuit of the rerefrigerant and any excess provided in the evaporator conduit near the bottom of the trap so that liquid refrigerant may reenter the evaporator conduit and flow back into the main portion of the evaporator. Small amounts of the liquid refrigerant which enter the orifice are atomized or sprayed into the vaporized refrigerant flowing through the evaporator conduit, due to the velocity of the refrigerant, and a mist or spray therefore enters the header. These small particles of liquid in the mist contain lubricating oil as well as liquid refrigerant and the admission of this spray to the suction line serves to return lubricating oil from the evaporator.

Referring now to the drawing, in Fig. 1 I have shown a bottled beverage cooler comprising a thermally insulated cabinet 10 provided with a door It in the top thereof. A compression type refrigerating machine (not shown) is arranged in a machinery compartment in the bottom of the cabinet below the bottom wall of a tank I2. A cooling unit which isarranged in the tank l2 and is supported on metal angle strips H3 at the bottom of the tank 12 includes an evaporator comprising a conduit M. The angle strips l3 support the condui Ill in spaced relation with the bottom of the tank, the several runs or turns of the conduit M being in the same plane and extending across the bottom of the tank. Liquid refrigerant is admitted to the evaporator through a capillary tube l5 and flows through aconnection Hi to the conduit M. The conduit M is constructed of extruded metal prowhen the compressor 24 has been stopped, the I viding a refrigerant tube It and a longitudinal flange l8 extending laterally on either side of the tube. so that the tube is arranged centrally on one side of the flange and so that the other side of the flange is fiat. A backwardly bent portion of the flange at the inlet end of the evaporator is secured by welding, or in any other suitable manner, at It) and 20 to the ends or return bends oftwo of the runs or loops of the evaporator. This provides a plurality of rigid loops and reenforces the evaporator. vaporized liquid refrigerant flows from the evaporator through a connection M to an upright cylindrical header or trap 22 where the liquid and vaporized refrigerant are separated, the vaporized refrigerant being withdrawn through a suction line 25.

As shown in Fig. 2, the evaporator conduit M is connected in the circuit of a refrigerating machine comprising a compressor 24 driven by an electric motor 25. vaporized refrigerant withdrawn from the header 22 flows through the suction line 23 to the compressor where it is compressed and is discharged to a condenser 26 where it is cooled and liquefied and from which it flows through the capillary tube l5 to the evaporator.

A substantial portion of the capillary tube 15 is secured in heat exchange relation withthe suction line 23 as indicated at 21. This provides a heat exchanger which increases the efficiency of the refrigerating machine; it also provides heat for vaporizing any small amounts of liquid refrigerant which, enter the suction line.

22 is clearly shown in Fig. 3. 2! which enters the header at the bottom extends upwardly and its open end communicates with the top portion of the header as indicated at 28. The suction line 23 extends downwardly into the top portion of the header and opens into the header as indicated at 29. Most of the liquid refrigerant entering the header through the opening 28 separates from the vaporized refrigerant and falls to the bottom of the header. In order to-return the liquid refrigerant from the header to the evaporator, and to facilitate the removal of oil from the evaporator, .a small aperture or restricted opening 30 is provided in the connection2l near the bottom of the header,

and it has been found that during the operation of the evaporator, small quantities of liquid rethrough the the connection 2|. A portion of the evaporator until such time as a slug of liquid refrigerant is formed which is blown out with the vaporized refrigerant into the header 22; the remainder of the liquid refrigerant enteringthe opening 30v is atomized and blown out of the opening 28 as a mist or spray. This facilitates oil removal as will be explained below. During the inactive portion of the refrigerating cycle,

liquid refrigerant in the header 22 drains back into the evaporator tube ll through the aperture 30. This liquid refrigerant which has been trapped in the header and returned to the evaporator is available to absorb heat from the water in the tank i2 during the off period of the cycle and some may remain to facilitate refrigeration when the compressor is started.

A mist of small particles of liquid refrigerant will be present in the vapor near the inlet 29 of the suction line, due to the atomizing or spraying action referred to above, withdrawn with the vaporized refrigerant through the suction line 23. This provides for the return of small amounts. of oil or lubricant which are mixed with or dissolved in the liquid refrigerant. The return of this lubricant is nec'essary,-since small amounts of lubricant are entrained unavoidably in the refrigerant discharged from the compressor.. These small amounts of liquid refrigerant are, vaporized and separated from the oil in the suction line. due to the absorption of heat from the warm liquid in the capillary tube in the portion 21 whichv duit, but also facilitates the removal of oil or The construction of the liquid trap or header The connection wardly extending other lubricant which is mixed with the liquid refrigerant and prevents the trapping of the lubricant in the evaporator.

A rack or grille 3| is supported on the upportion of the flange l8 and is provided to support bottles or other articles above the refrigerant conduit within the tank l2.

During the operation of the beverage cooler described above the tank I2 is partially filled with water. Bottles of beverage or other articles are placed on the rack 3| in the water. Heat from the bottles is transferred to the refrigerant in the conduit l1 through the water in the tank, and liquid refrigerant in the conduit is vaporized by the absorption of heat and is withdrawn through the connection 2| and the header 22 and returned to the compressor tion line 23. Any slugs of liquid refrigerant discharged through the connection 2|. are trapped in the header 22 and the liquid is returned in small quantities through the opening 30 so that it is again available to provide refrigeration withand will be.

through the suc stricted opening in said outlet tube adjacent the in the tube 11. When the compressor has stopped any liquid refrigerant remaining in the header 22 returns to the tube [1 .where it is readily available for cooling of the water in the tank [2.

While I have shown a particular embodiment of my invention in connection with a beverage cooler of the wet type, other applications will readily be apparent to those skilled in. the art. I do not, therefore, desire my invention to be limited to the particular construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as'newand desire to secure by Letters Patent of the United States is: p

1. A cooling unit for refrigerating machines including a refrigerant vaporizing conduit, a fixed restrictor for controlling the admission of refrigerant to said conduit, a vapor connection a for removing vaporized refrigerant from said conduit, a liquid and vapor separating header between said conduit and said vapor connection, said conduit having a portion thereof extending through said header and opening into the upper portion of said header and a restricted opening providing communication between the lower portion of said header and said-conduit for affording drainage of liquid refrigerant from said header back into said conduit.

2. A cooling unit for refrigerating machines including a refrigerant vaporizing conduit, a fixed restrictor for controlling the admission of liquid refrigerant to said conduit, an upwardly extending outlet tube for said conduit, said conduit having a portion thereof arranged in a horizontal plane below said tube, a liquid and vapor separating header arranged about said tube and above said portion of said conduit, said tube opening into the upper portion of said header, a connection for withdrawing vaporized refrigerant from said header and a restricted opening in said tube adjacent the bottom of said header for affording drainage of liquid refrigerant from said header back into said portion of said conduit.

3. A cooling unit for refrigerating machines including a continuous extended refrigerant vaporizing conduit arranged in a substantially horizontal plane, a restrictor tube for controlling the admission of liquid refrigerant to said conduit, an upwardly extending outlet connection for said conduit, an elongated upwardly extending liquid and vapor separating header, said out- -let connection opening into said header in the upper portion thereof, a suction connection for removing vaporized refrigerant from said'header and means providing a restricted opening between the lower portion of said header and said conduit for affording drainage of liquid refrigerant from said header back into said conduit.

4. A cooling unit for refrigerating machines including a continuous refrigerantconduit arranged to extend back and forth in a substantially horizontal plane whereby it may be positioned adjacent the bottom of a compartment to be cooled, a restrictor tube for controlling the admission of liquid refrigerant to said conduit, an elongated upwardly extending header arranged above said conduit and an'outlet tube for said conduit extending through the lower portion a of said header and opening-into the upper portion thereof for removing refrigerant from ,said conduit, a vapor connection for removing vaporized refrigerant from said header, and a rebottom of said header for affording drainage of liquid refrigerant from said header back into said conduit.

5. A cooling unit for refrigerating machines including a refrigerant vaporizing portion and a liquid and vapor separating header, a conduit opening into the upper portion of said header for connecting said header and said vaporizing portion, means for admitting liquid refrigerant and entrained lubricating oil to said vaporizing portion, means for withdrawing vaporized refrigerant from said header, and means for admitting small amounts of liquid refrigerant and oil to said conduit near the end thereof for producing a mist of liquid refrigerant in the vaporized refrigerant entering said header whereby the removal of small particles of liquid refrigerant and oil from said evaporator is facilitated.

6. A cooling unit for refrigerating machines including a refrigerant vaporizing conduit, 2. fixed restrictor for controlling the admission of refrigerant and entrained lubricating oil to said conduit, a vapor connection for removing vaportion between the lower portion of said headerand said conduit for affording drainage of liquid refrigerant from said header back into said conduit and for producing a mist of liquid refrigerant and oil in the vaporized refrigerant entering said header to facilitate the removal of small amounts of liquid refrigerant and oil from said evaporator.

'7. An evaporator for refrigerating machines comprising a refrigerant evaporating conduit extending back and forth to provide a plurality of runs in a substantially horizontal plane, and a a longitudinal flange formed on said conduit and extending upwardly from the plane of said conduit for supporting a grille or the like in spaced relation with said conduit.

8. A refrigerant evaporator including a conduit formed of extruded metal, said conduit comprising a tube and a flat strip constituting a longitudinal flange on said tube, said conduit being bent to provide a plurality of runs arranged in a common horizontal plane and said flange extending upwardly from the horizontal plane and providing a support for a grille or the like.

- a plurality of rigid loops, said flange extending above the plane of said conduit and providing a;

support for holding a grille or the like in spaced relation with said conduit. i

10. A refrigerant evaporator comprising a refrigerant vaporizing conduit formed with a longitudinal flange extending along one side thereof, said conduit lying on one side of said flange and the other side of said vflange presenting a flat surface; said conduit beingbent to provide, a

plurality of runs connected by return bends in a common plane with said flange extending transversely from the plane, a portion of said conduit being bent back into engagement with the flat sides of the flange on a plurality of the return bends of said runs, a portion of said flange on the backwardly bent portion of said tion for removingvaporized refrigerant from said conduit, a liquid and vapor separating header between said conduit and said vapor connection, said conduit having a portion thereof extending through said header and opening into the upper portion of said header and a restricted opening conduit being secured to the portions of said flange adjacent said return bends with the flat sides of said portions of said flange in face engagement whereby a plurality of rigid loops of said conduit are formed.

11. A cooling unit for refrigerating machines providing communication between the lower portion of said header and said conduit for affording drainage of liquid refrigerant from said header back into said conduit and for producing a mist of liquid refrigerant and oil in the vaporized refrigerant entering said header to facilitate the removal of small amounts of liquid refrigerant and oil from said evaporator.

ROMAN c. WARNEKEt 

